stirling



(No Model.) 2 Sheets-Sheet 1' A. STIRLING.

MACHINE FOR BENDING TUBES.

No. 493,390. Patented Mar. 14, 1893.

W/TNESSES: INVENTOH flZZag/Jizrlzgy W I IZVMMAJQ A TTOHNYE rs 2Sheets-Sheet 2.

A. STIRLING.

MACHINE FOR BENDING TUBES.

(No Model.)

N0. 493,390. Patented Mar. 14,1893.

WITNESSES: M' W NITED STATES ATENT QFFIQE.

ALLAN STIRLING, OF NEW YORK, N. Y.

MACHINE FOR BENDlNG TUBES.

SPECIFICATION forming part of Letters Patent No. 493,390, dated March14, 1893.

Application filed September 1 1892. Serial No. 444,770. (No model.)

To all whom it may concern.-

Be it known that I, ALLAN STIRLING, a citizen of the United States,residing at New York, in the county and State of New York, haveinventednew and useful Improvements in Machines for Bending Tubes, of which thefollowing is a specification.

This invention relates to certain improvements in machines for bendingmetal tubes, such as boiler tubes made of wrought iron or of steel.-

The improvements which constitute my invention, are pointed out in thefollowing specification and claims and illustrated in the accompanyingdrawings in which:

Figure 1 represents a plan or top view showing the parts in positionbefore the operation of bending has commenced. Fig. 2 is a sideelevation looking in the direction of arrow 1 (Fig.1). Fig. 3 is a sideelevation looking in the direction of arrow 2 (Fig. 1). Fig. 4 is aplan, or top view showing the parts in position while the bendingoperation is progressing.

In the drawings the letter A designates a frame which forms the bearingsfor three arbors B, O, C. On the upper end of the arbor B is firmlymounted the bending die D which in the example shown, consists of asegment provided in its periphery with a semicircular groove a, thediameter of which corresponds with the diameter of the tubes to be bent.For tubes of different diameters different bending dies must beprovided. WVith the bending die is combined abridle E which serves tosecure the end of the tube to be bentin the semicircular groove a. Inthe example shown in the drawings, this bridle consists of an eyebolt,the shank b of which extends through a lug 0 connected to the bendingdie (Figs. 1 and 4) while the eye 01 of said eye bolt is oblong (Fig. 3)so that it can embrace the end of the tube to be bent and also a lip ewhich projects from the front edge of the bending die and serves as asupport for the front end of the tube. The shank b of the eye bolt isprovided with a screw thread and with a nut f and by screwing up thisnut, the end of the tube can be firmly clamped on the bending die. Inorder to prevent the end of the tube from being crushed, a plug g may beinserted.

011 the arbor C is eccentrically mounted the retaining die E and ahandle F serves to turn the arbor C. If this handle is turned to theposition shown in Fig. 1, the retaining die E is moved away from thebending die D so that the tube can be conveniently introduced betweenthe two dies and if the handle F is moved to the position shown in Fig.4 the retaining die is brought to bear upon the tube so as to hold thesame in the semicircular groove a of the bending die. The retaining dieis provided in its circumference with a semicircular groove h (Fig. 3)corresponding in its diameter to the semicircular groove a in thebending die so that when the two dies are brought together, the groovesa and h embrace the tube. In the example shown in the drawings, theretaining die E is mounted loosely upon a wristpin 2' which is securedeccentrically in a disk j mounted firmly upon the arbor O and the handleF is firmly mounted upon the outer end of eccentric wrist pin 1'.

Behind the retaining die E is situated the stop G to prevent the tubefrom flapping as the operation of bending progresses.

In the example represented by the drawings, I have shown a cylinder Hcontaining a piston to which motion is imparted by hydraulic pressure.The piston rod I carries a rack bar J which engages a toothed segment Kmounted on the arbor B.

What I claim as new, and desire to secure by Letters Patent, is

1. In a machine for bending tubes, the combination with the bending dieD, of the bridle E having an oblong eye d a lip 6 projecting from thebending die into this oblong eye and means for imparting to the bendingdie a rotary motion, substantially as described.

2. In a machine for bending tubes, the combination with the bending dieD and the bridle E, of a roller E mounted eccentrically on an arbor O, ahandle for turning this arbor and means for imparting to the bending diea rotary motion, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

ALLAN STIRLING.

Witnesses:

IVIARGARET A. STIRLING, ALIsoN B. STIRLING.

